Repair Oversized Outlook PST File by Splitting or Compressing

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  • Published on
    June 5th, 2018
  • Updated on
    September 23, 2022
  • Read Time
    7 minutes
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Summary:- It is not easy for an Outlook user to manage a large PST file because it consists of thousands of emails and other mailbox items. On the other hand, oversized PST files are prone to corruption and you can lose some of your crucial data if it has become corrupted. Therefore, here you can see various ways to repair oversized Outlook PST File either by splitting or compressing it. You can also remove duplicate emails from the PST file to reduce its size. If in case your PST file is corrupted due to its large size then you will have to use the PST Recovery Tool. Otherwise, you can deal with the Oversized PST File issue by compressing, splitting, or removing duplicate emails from the file.

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Microsoft Outlook is a popular email client that offers you a wide range of features. Apart from being an email application, it includes a contact manager, calendar, task manager, note-taking, journal, and web browser. It creates an Outlook data file, commonly known as PST, to store emails and other data which include contacts, calendars, tasks, notes, journals, as well as attachments. PST (personal storage table) file is of two types: ANSI and Unicode. The older versions like Outlook 2002 and earlier use ANSI format to store PST files. Whereas Outlook 2003 and later versions use Unicode format. The ANSI and Unicode PST files have different size limitations.

What is an Oversized PST File?

A PST file is called oversized when it crosses its maximum size limit. An ANSI PST file can store the mailbox content up to 2 GB. On the other hand, a Unicode PST file has a maximum size limitation of 20 GB (Outlook 2003 & 2007) and 50 GB (Outlook 2010 & later versions). The fact says that an oversized PST file is always prone to corruption. In fact, the size limitation issue is considered one of the main reasons for corruption.

If you’re an active Outlook user, you’re likely to send and receive a large number of email messages each and every day. Having a large number of mailbox data will increase the PST file size. And one day, it’ll reach its maximum size. Whenever this happens, you’re likely to face severe problems including Outlook performance issues. And the situation becomes worse when the PST file crosses its maximum size.

Below are the error messages you may encounter while trying to open a corrupt PST file:

Common Errors for Oversized PST File

  • The filename.pst is not a personal folder file.
  • An unexpected error prevented access to this file. Use ScanDisk to check the disk for errors, and then try using the Inbox Repair tool again.
  • The filename.pst has reached its maximum size limit.
  • Errors have been detected in the Outlook PST file. Quit all mail-enabled applications.

How to Fix An Oversized PST File?

If you have a too large PST file, you must do the needful in order to protect it from being Oversized and get corrupted. There are three different ways to deal with an oversized PST file:

Split PST File

If you notice that the Outlook data file has reached its maximum size, you can split PST into two or multiple parts. By doing this, you’ll get two or multiple PST files instead of one. You can follow the steps given below to split the oversized PST file into small-size PSTs.

  • Download and Install PST Split Tool on your Device.
  • Add the Oversized PST File that you want to split.
  • Choose the Basis of Split whether size, date, sender, or folder.
  • Define the size of each PST file.
  • Finally, click on the Split button and your oversized PST file will get split into multiple small PST files.

Compress PST File

Also, you can compress PST files in order to get enough space to store more mailbox content. You can compress or compact PST files by using the built-in feature of MS Outlook. You can follow the steps given below to compress large PST file and reduce its size.

  • Download and Install PST Compress Tool.
  • Add a Large PST file to the Tool.
  • Choose the Compression option whether you want to compress emails and attachments separately or together.
  • Finally, click on the Start Compression Button and your Large PST File will be compressed.

Remove Duplicate Items

Duplicate items are majorly responsible for an oversized PST file. It may happen that the Outlook data file has a large number of duplicate items which have occupied all the free space. So removing duplicate items from the PST file is a better option to deal with an oversized PST file.

Methods to Repair a Corrupt Oversized Outlook PST file

The above methods will help you to reduce the size of your PST file and fix PST oversize issue. But if your PST file is oversized and it is corrupted then you will have to repair it. Here you can see the prominent methods to repair a corrupted oversized PST file.

Method 1

Most of the time we prefer using a valid backup which is considered the best way to recover a corrupt PST file that is too large to be recovered. If you notice anything wrong or encounter an error message while opening a PST file, this means the file is corrupt. You’re lucky if you take regular backups of your PST files. You can easily restore the PST files from the backup. But if there’s no backup available, you should use the Inbox Repair tool, commonly known as the scanpst.exe utility. To run the Inbox Repair tool, you must locate its executable file.

Note: The scanpst.exe location varies according to Outlook as well as the Windows system you’re using. Interested users may refer to this article – SCANPST Location – Locate the Inbox Repair Tool

Method 2

Sometimes it might be a challenging task to repair oversized Outlook PST files. If you have a large PST file to repair, the scanpst.exe utility may take ample time. Even there’s no guarantee that the Inbox Repair tool will surely work. In such a situation, you should always look forward to a professional solution like the Advanced Outlook Recovery tool. It’s an amazing Outlook Recovery solution provided by SysInfoTools Software. Unlike the Inbox Repair tool, it doesn’t take much time to scan and repair PST files of any size. In fact, there’s no such size limitation, i.e. you can select a PST file up to 80 GB with no problem.

The “batch recovery” feature is the best part of this Outlook Recovery tool. This means you can select any number of PST files at a time and recover data from them simultaneously. To repair oversized Outlook PST files, you have three recovery modes: Standard, Advanced, and Deep.


The Outlook Recovery tool provided by SysInfoTools Software is available with the free demo version. Before purchasing the software, you must download its demo for free evaluation purposes. By using the demo version, you can save the first 25 email items of each mailbox folder of the selected PST files. To overcome this limitation, you must place an order for the licensed version of this software. With this amazing Outlook Recovery tool, it’s no more a challenge to repair oversized Outlook PST file.

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